This invention relates to an adjustably tiltable pneumatic device and, more particularly, to a pneumatic device which can be tilted so that an output pressure can be adjustably selected for a given input pressure.
Pneumatic devices known in the prior art cover a wide range of functions such as amplification, high-low pressure selection, pressure diverting, comparison, addition, subtraction and other mathematical functions. Some of these devices require adjustment of a setpoint so that any output from the device will be a function of the difference between the input pressure to the device and the setpoint. Others, if not all, of these devices also require a calibration adjustment which typically involves a manually adjustable control for adjusting the output pressure until it is at a desired level for a given input pressure. That is, during the calibration operation, a predetermined input pressure is supplied to the device and the calibration adjustment mechanism is adjusted until the output pressure for that input pressure achieves a desired level.
The mechanisms by which the output pressure can be manually adjusted with respect to the input pressure for any selected function such as set point control or calibration has heretofore been performed by a spring arrangement after the device is mounted in a permanent position. According to this arrangement, the manually adjustable knob or lever operates against a spring which in turn operates against a pressure controlling element within the pneumatic device. A pneumatic input pressure is typically applied against this element opposite to the force applied by the adjustment spring.
The present invention eliminates these springs and, instead, adjusts the output pressure from the pneumatic device in response to the tilting of the device so that a given output pressure can be selected for a given input pressure. This arrangement eliminates unnecessary parts and reduces the spring rate of the pneumatic device.